It has been known before to construct a ground working apparatus which is attachable to such a tractor such that the implement can be controlled in direction by cables between the tractor and the attached implement. In this regard, attention is called to Wise, U.S. Pat. No. 1,242,505.
It has not been known or taught before, moreover, to construct an apparatus which is attachable to an independently powered truck or tractor for controlling a ground working implement remotely from the truck, wherein the operator remains.
It has been known before also to construct independently powered, operable lawn mowing instruments, and similar type ground working instruments Oftentimes, it is undesirable for one reason or another for an operator operating such instruments to be physically close to such an instrument, as is required in lawn mowing instruments which must be pushed or pulled. Thus, many lawn mowing devices have been invented and produced which operate independently of constant operator supervision. Most of these devices, however, operate on some mechanical, electrical or optical sensing means which sense boundaries such as tall grass, walls and the like. Thus, once such an instrument is started the device follows a predetermined path until a mission is completed. In the meantime, the operator can remove from the premises.
Devices attachable to an independently powered truck have been known, also. In many cases such devices are ground working or farm implements. Such as implement frequently is constructed so as to be attached by a hitch to a tractor or other similar, independent power source.
In many applications of independently operated ground or grass working instruments, the ground or grass working instrument must follow a path on relatively level terrain. Any terrain which becomes excessively hilly, or terrain which is marked by bolders, holes, or other features which the sensing elements of such a device cannot detect, individual operator supervision is required in close proximity to the device. Furthermore, oftentimes it is desired to maneuver such devices as a lawn mower into areas where an operator cannot follow comfortably in such close proximity.
Hereafter in this description, the term truck and tractor shall be used synonymously to indicate a selectively movable, semi-permanent station from which an operator may control a device capable of movement independent of the truck or tractor.